Chuck for watch-makers  lathes



will be daring, as shown at c.

UNITED STATESr PATENT OFFICE.

'AUfeUsrUsEnENcm 0E cI-IIeAeo,ILL1NoIs.

CHUCK FOR WATCH-MAKERS LATHES.

SPECIFICATION-forming part of Letters Patent No. 237,105, dated February1, 1881.

Application filed January 27, 1880.

To all whom it may concern Be it known that I, AUGUSTUS FRENCH, ofChicago, in the countyl of Cook and State of Illinois, have invented'certain new and useful Improvements in Chucks for Watch-Makers Lathes,of which the following, in connection with the accompanying drawings, isa specification.

In the drawings, Figure l is a side elevation of `a lathe-chuckembodying my invention; Fig. 2, an end view thereof; Fig. 3, a sectionin the plane of the line ac :c of Fig.'1; Fig. 4, a section in theplane'of the line y y of Fig. l Fig. 5, a section'in the plane of theline z c of Fig. 1 5 Fig. 6, a vertical central longitudinal section ofthe forward part of the case or shell of the chuck Fig. I7, a side viewof 'the inner or sub chuck, and Fig. 8 a vertical central longitudinalsection of the outer spring-jaws.

Like letters of reference indicate like parts.

A represents the rear part of the shell or case of the chuck, and a is ashoulder near the forward end of this. part of the shell. The part A ishollow, and b b are slots therein. A deep socket or recess, c, exists inthe rear end of the part A.

B is a stemV or spindle extending from the rear end of thepart A.

C is the forward part of the shell or case of the chuck. The part C isalso hollow or tubular, and is sufficiently slender to pass quite freelyor loosely into the forward end of the part A, so as to leave a slightspace between these two parts, as indicated at d, Fig. 3. The forwardinner edge of the part C is chamfered, so that the outer end or mouth ofthe said part A collar or shoulder, D, is also made on the forward endof the part C. v

E E are extensions projecting rearward from the shoulder D. When theparts A and C are arranged together the forward end of the part A nearlystrikes the face of the shoulder D, and the rear ends of the extensionsE E nearly strike the face ofthe shoulder a, and a considerable' spaceexists between the part A and theunder faces of the extensions E E, asindicated in Figs. 3 and 4.v A. considerable space also exists betweenthe extensions E E. rlhe parts A and C are connected by means of cementarranged underneath the extensions E E, as shown at F.

G is a screw or pin entering the part C.

H is a split-chuck, and f f are annular beveled grooves sunken in theinner faces of the jaws H H' of the chuck H. The outer faces of these`jaws are flaring, as usual, and the chuck is adapted to enter the partC of the shell or case, and is long enoughvto also enter the socket orrecess c when the chuck is in position for work.

On the rear end of the cluck His a rounded enlargement, g, made tonicely flt the socket c, or nicely enough to prevent the rear end of thechuck from being moved laterally in the said recess, but not fitting tooclosely to prevent a slight wabbling movement of the outer end of thechuck, and not preventing the easy insertion and removal of the chuck. Iterm the part g a back-centen7 and the socket or re Ycess c I terni theback-center hearing.

It will be observed that the chuck H may be moved back and forth in thesocket or re cess c, and that the enlargement or rib g will always havea bearing against the horizontal part of the wall inclosing the saidrecess. By this means the said chuck, wherever set, will have aback-center bearing which will admit of the centering of the outer endof the said chuck, it being remembered that this chuck will be drawnfarther rearward when the object seized is small than when it iscomparatively large. In other words, by employing whatmay be termed asliding backcenter,7 objects of different sizes may be grasped andcentered without freeing the cement.

0n that part of the chuck H which passes out rearward through the partC, I make a screw-thread, h, and I is a nut run upon this screw-threadedpart and having notches c' made in its perimeter. The chuck H may besecured to the part C by running the nut upon the screw-threaded partafter passing the chuck through or into the part C. The chuck may thenbe either tightened or loosened so as to either contract or expand itsjaws, by turning the nut in the proper direction, for the nut bearsagainst the inner end of the part' G, and when screwed toward that endtightens the chuck and contracts its jaws, which, however, will expandwhen the nut is turned in the opposite direction. To prevent the chuckfrom being turned with the nut, I

sink a groove, j, longitudinally along the face IOO of the chuck, andinto this groove the screw G enters. When the chuck and the part C thusconnected are arranged in the part A, access may be had to the nut Ithrough the slots b b, or either thereof. In other respects the chuck H,which I term the outer chuck,7 may be constructed in the usual manner.

J is an inner or sub chuck, sufiiciently slender to enter the chuck H.Near the outer end of the chuck J are the annular beveled ribs jeff',arranged with relation to the grooves ff, as shown in Fig. 3. The chuckJ is also a split chuck; but7 in addition to the usual splits k k, Imake the deep splits k k', entering the rear end of the chuck andextending much beyond the rear ends of the splits k lr, as is clearlyshown in Fig. 7. These splits I term zigzag splits. In other respectsthe chuck J may be made in the usual manner.

The manner of using these parts when they are made and arranged togetherin the way shown and described is as follows: The object to be operatedupon is placed in the chuck J. The yielding jaws lnay be forced downupon and made to clamp the object tightly by turning the nut I in theproper direction. By making upon the chuck J the two ribs ff, that chuckhas two bearings against the inner face of the chuck Il, and hence theinner chuck, by bein gthus prevented from wabblin g, will hold theobject steadily or prevent it from wabbling. By making the hearing-facesinclined, in the manner shown and described, the chuck is especiallywell adapted to hold tapering objects rmly, for as the chuck J iscompressed bythe chuck H, the chuck J will be pushed forward, and as itmoves forward the inner or most rearward rib,f, will be pushed down, andhence the tapering or smaller part ofthe object will be more conlinedthan if the forward end merelyof the inner chuck should be contracted.Whether the object be either straight or tapering, it will be firmlyseized and held, owing to either some or all of the provisions abovedescribed as intended for that purpose. After the object is thus iirmlyseized it may be easily centered by warming the cement cushion F untilit is `yielding by rotating the mandrel and by holding any suitableobject steadily on the outer end of the object in the chuck. As soon asthe object in the chuck is properly centered the cement should beallowed to become cold, when all the parts will be held firmly in theirproper places, the backcenter keeping its proper position always withrelation to its bearing, and the remaining parts being suiicientlymovable when the cement is yielding to allow the forward end of theobject to be brought to a true central position. These results I attainto a great extent, for the reason ttllat the inner chuck is madeextremely dexib e.

It will be perceived that it is immaterial whether the enlargement g beon the chuck H or projects from thc recess or socket c.

It will also be perceived that the same rcsult will follow if therelative positions of the grooves ff and ribs fj be changed.

It may also be here stated that it is not essential that all thebearing-surfaces between the inner and outer chucks should be inclinedor beveled, for it is obvious that if the ribs j7 j?, for example, benot inclined or beveled they will operate in the manner described inconnection with grooves ff, having inclined sides, provided the saidgrooves be sufficient] y wide for that purpose.

The spaces between the parts E E serve as slots or perforations to admitof the contraction and expansion ot' the cement.

What has been hereinbefore stated with reference to the forward movementof the chuck J in the chuck H when the former is compressed by thelatter had reference only to the result following such compression whenthe smaller end of a tapering object was inserted in the chuck J. Whensuch an object is so inserted, and the chuck J is compressed orcontracted until it pinches the larger part ot' the object, the outerrib, f', being over, or nearly over, such larger part, cannot be pressedfarther toward the object. In other words, the outer end of the chuck Jwill be no longer yielding toward the object init; but, as the object istapering, and as its smaller end was rst inserted, its smaller portionwill not be pinched until after its larger part is. The inner rib, ftherefore, may be pressed in toward the smaller part of the object untilthat part is pinched also by the chuck J. With this explanation, and byreference to Fig. 3, it will be perceived that the chuck J will bepushed slightly forward by tightening the chuck H upon it, owing to theform and arrangement of the ribs f' f', and of the parts against whichthey are intended to bear, it being un erstood that the smaller end of atapering obJect has been rst inserted in the chuck J, and that the innerrib, f can therefore yield to the chuck H after the outer rib, f', hasceased to vield toward the object. This forward movement of the chuck Jwill cause it to pinch the tapering end of the object as well as itslarger part, and then the forward movement will cease, for it will beresisted by the inner rib, f', which will no longer yield toward theobject. Tapering objects may thus be very firmly held. The chuck J willbe pushed in the reverse direction or inward if the larger end of atapering object be first inserted in the chuck J; but it' the object henot tapering the chuck J will not be moved longitudinally in the chuck Hwhen the latter is tightened.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. The combination, iu a chuck, of the yielding jaws H' H', havingtherein the recesses or grooves f f sunken in their inner faces, and ofan inner split chuck having on its outer face the correspondingly-formedribs f f', substantially' as and for the purposes specitied.

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2.' A chuck wherein two parts are adapted, substantially as described,to be temporarily united by means of a cushion of cement, and in thecuter'of which parts are the extensions E E, having spaces between andbelow them to admit of the contraction and expansion of the cement,substantially as and for the purposes specified.

3. The combination, in a chuck, of the deep socket, recess orback-center bearing c, and of the longitudinally-adjustable split chuckH, having on its rear end the annular rib or back center g, adapted totit into the said socket or recess c, and bear against the wall thereofduring the adjustment longitudinally of the chuck H, substantially asand for the purposes specified.

4. The combination, in a chuck, of the hollow cylindrical part A, havingtherein the slots b b, the hollow removable part C, the

screw-threadedv chuck H, having therein the groove j, the screw G, andthe serrated nut JI, substantially as and for the purposes speci- 5. Thecombination, in a chuck, of the hollow cylindrical part A and the hollowremovable cylindrical part C, the latter adapted to enter the part Afreely 0r loosely, and having thereon the rearward extension E E,forming a space between the parts A and C for the reception of cement,and keeping the cement from contact with the working parts of the chuck,substantially as and for the purposes specified.

AUGUSTUS FRENCH. Witnesses:

F. F. WARNER, W. S. BAKER.

